Consecutive hybrid mechanism boosting Na+storage performance of dual-confined SnSe2 in N,Se-doping double-walled hollow carbon spheres

Rationally designed hierarchical structures and heteroatomic doping of carbon are effective strategies to enhance the stability and electrical conductivity of materials.Herein,SnSe_(2)flakes were generated in the double-walled hollow carbon spheres(DWHCSs),in which N and Se atoms were doped in the carbon walls,to construct SnSe_(2)@N,Se-DWHCSs by confined growth and in-situ derivatization.The N and Sedoped DWHCSs can effectively limit the size increase of SnSe_(2),promote ion diffusion kinetics,and buffer volume expansion,which can be proved by electron microscope observation and density functional theory calculation.Consequently,the SnSe_(2)@N,Se-DWHCSs as an anode material for sodium ion batteries(SIBs)demonstrated a distinguished reversible capacity of 322.8 mAh g^(-1)at 5 A g^(-1)after 1000 cycles and a superior rate ability of 235.3 m Ah g^(-1)at an ultrahigh rate of 15 A g^(-1).Furthermore,the structure evolution and electrochemical reaction processes of SnSe2@N,Se-DWHCSs in SIBs were analyzed by exsitu methods,which confirmed the consecutive hybrid mechanism and the phase transition process.

High-yield production of porous carbon spheres derived from enzymatic hydrolysis lignin for zinc ion hybrid capacitors

The widespread implementation of supercapacitors is hindered by the limited energy density and the pricey porous carbon electrode materials.The cost of porous carbon is a significant factor in the overall cost of supercapacitors,therefore a high carbon yield could effectively mitigate the production cost of porous carbon.This study proposes a method to produce porous carbon spheres through a spray drying technique combined with a carbonization process,utilizing renewable enzymatic hydrolysis lignin as the carbon source and KOH as the activation agent.The purpose of this study is to examine the relationship between the quantity of activation agent and the development of morphology,pore structure,and specific surface area of the obtained porous carbon materials.We demonstrate that this approach significantly enhances the carbon yield of porous carbon,achieving a yield of 22%in contrast to the conventional carbonization-activation method(9%).The samples acquired through this method were found to contain a substantial amount of mesopores,with an average pore size of 1.59 to 1.85 nm and a mesopore ratio of 25.6%.Additionally,these samples showed high specific surface areas,ranging from 1051 to 1831 m2·g^(−1).Zinc ion hybrid capacitors with lignin-derived porous carbon cathode exhibited a high capacitance of 279 F·g^(−1) at 0.1 A·g^(−1) and an energy density of 99.1 Wh·kg^(−1) when the power density was 80 kW·kg^(−1).This research presents a novel approach for producing porous carbons with high yield through the utilization of a spray drying approach.

Ordered mesoporous carbon spheres assisted Ru nanoclusters/RuO_(2) with redistribution of charge density for efficient CO_(2) methanation in a novel H2/CO_(2)fuel cell

Efficiently reducing carbon dioxide(CO_(2))into carbon chemicals and fuels is highly desirable due to the rapid growth of atmospheric CO_(2)ncentration.In prior work,we described a unique H/CO_(2)fuel cell driven by low-valued waste heat,which not only CO_(2)nverts CO_(2)to methane(CH_(4))but also outputs electrical energy,yet the CO_(2)reduction rate needs to be urgently improved.Here,a novel Ru-RuOcatalyst with heterostructure was grafted on mesoporous carbon spheres by in situ partially reducing RuOinto ultrasmall Ru clusters(~1 nm),in which heteroatom-doped carbon spheres as a matrix with excellent CO_(2)nductivity and abundant pores can not only easily CO_(2)nfine the formation of Ru nanocluster but also are beneficial to the exposed active sites of Ru CO_(2)mplex and the mass transport.CO_(2)mpared to pure RuOnanoparticles supported on carbon spheres,our CO_(2)mposite catalyst boosts the CO_(2) nversion rate by more than 5-fold,reaching a value of 382.7μmol gcat.h-1at 170℃.Moreover,a decent output power density of 2.92 W mwas obtained from this H2/CO_(2)fuel cell using Ru-RuOembedded carbon spheres as a cathode catalyst.The Ru-RuOheterostructure can modify the adsorption energy of CO_(2)and induce the redistribution of charge density,thus boosting CO_(2)reduction significantly.This work not only offers an efficient catalyst for this novel H_(2)/CO_(2)fuel cell but also presents a facile method to prepare Ru nanoclusters.

Chestnut shell-like N-doped carbon coated NiCoP hollow microspheres for hybrid supercapacitors with excellent electrochemical performance

In this work,transition metal phosphides(TMPs)were reinforced by a solvothermal synthesis method and in situ polymerization in dopamine with one-step phosphating and carbonizing process to form chestnut shell-like N-doped carbon coated NiCoP(NiCoP@N-C)hollow microspheres.Excellent morphologic structure is still reflected in NiCoP@N-C,which is suitable for rapid electron and electrolyte transfer.Benefiting from the excellent structure,the coating of N-doped carbon,and the synergistic effect of Ni and Co,NiCoP@N-C reveals excellent electrochemical properties(high specific capacitance of 1660 F·g^(-1)(830 C·g^(-1))at 1 A·g^(-1)).In addition,a NiCoP@N-C//carbonization HKUST-1(HC)achieves high specific energy of 51.8 Wh·kg^(-1),ultrahigh specific power of 21.63 kW·kg^(-1),and excellent cycling stability up to 10000 cycles(a capacitance retention of 96.7%).The results show that the NiCoP@N-C electrode material has a wide application in supercapacitors and other energy storage devices.

Porous carbon spheres anode with the stable output of low delithiation plateau and constant delithiation ratio for lithium ion hybrid capacitor

Porous carbon spheres derived from the facile hydrothermal treatment associated with the calcination process exhibit the good spherical morphology and unique porous structure.For the Li-based half-cell test,porous carbon spheres electrode not only exhibits larger reversible capacities and better compatibility as compared to the widely-used graphite,but also provides stable delithiation plateaus under different current density.Additionally,the delithiation ratio below 1 V almost accounts for a constant value(around 70%)with the increase of current density,evidencing that Li intercalation storage is the dominant model and Li insertion/extraction processes are propitious.The lithium ion hybrid capacitor configured with S-doped mesoporous graphene and porous carbon spheres as cathode and anode,delivers satisfied energy and power densities(up to 177 Wh kg^(−1) and 12,303 W kg^(−1),respectively)as well as long-term cyclability,which is superior to the corresponding S-doped mesoporous graphene//graphite and activated carbon//porous carbon spheres.In addition,the developed synthesis strategy is in favor of the realization of the scalable production of porous carbon spheres.

高效氧化亚铜/多壁碳纳米管亚微米复合球的制备及其性能研究

报道了一种利用氨水作为助剂,无需表面活性剂为模板,采用微波技术,2 min一步合成Cu2O/多壁碳纳米管(MWCNTs)亚微米复合球的新方法,其特点是简单、成本低、快速、高效,可以推广至其他过渡金属/MWCNTs复合球体系.谱学表征(XRD,SEM,TEM,DSC等)研究表明,氨水是控制Cu2O/MWCNTs亚微米复合球形成的关键,既是球状体形成的引导剂,又是Cu2O和MWCNTs在分子水平上结合的"粘合剂";Cu2O/MWCNTs亚微米复合球能高效催化高氯酸铵热分解,降低其高温热分解温度至326.5℃,较纯高氯酸铵的高温热分解温度下降了63.8℃,比纯MWCNTs及纳米Cu2O促进的高氯酸铵高温热分解温度分别降低了47.1和5.7℃;且热分解反应速率大大提高,其促进高氯酸铵表观分解放热量增至为纯高氯酸铵的1.3倍.Cu2O/MWCNTs亚微米复合球的高催化活性可能源于纳米Cu2O和MWCNTs的协同催化作用.

聚丙烯原位碳化合成石墨烯负载碳球纳米杂化材料研究

本研究以氧化石墨烯（GO）为模板负载氢氧化镍（Ni（OH）2）和氢氧化钴（Co（OH）2）纳米粒子,并分别熔融共混到聚丙烯（PP）中,利用PP原位碳化方法成功制备出GO负载碳球纳米杂化材料。利用X射线衍射（XRD）和拉曼波谱分析（Raman）对合成的Ni（OH）2、Co（OH）2、GO负载Ni（OH）2和GO负载Co（OH）2进行表征。采用透射电子显微镜（TEM）、XRD和Raman等对合成的石墨烯负载碳球纳米杂化材料的形貌结构和物理性质进行表征。结果表明：利用PP原位碳化可成功制备两种不同类型的石墨烯负载碳球纳米杂化材料。